Nanowerk July 13, 2023 Contrary to topological insulators, topological semimetals possess a nontrivial chiral anomaly that leads to negative magnetoresistance and host to both conductive bulk states and topological surface states with intriguing transport properties for spintronics. Researchers at the University of Minnesota fabricated highly ordered metallic Pt3Sn and Pt3SnxFe1-x thin films via sputtering technology. Systematic angular dependence (both in-plane and out-of-plane) study of magnetoresistance presented surprisingly robust quadratic and linear negative longitudinal magnetoresistance features for Pt3Sn and Pt3SnxFe1-x, respectively. They attributed the anomalous negative longitudinal magnetoresistance to the type-II Dirac semimetal phase (pristine Pt3Sn) and/or the formation of tunable […]
Tag Archives: Topological semimetals
Scientists discover semi-metallization and novel photoelectric behavior in lead iodide under high pressure
Phys.org May 10, 2023 Topological semimetals have advantages in achieving highly sensitive, low energy photodetection with ultrafast operation. Although various semimetals have been explored recently, new semimetals are still being pursued for high-responsivity photodetectors with broadband response. Researchers in China reported a pressure-induced semiconductor–semimetal transition in two-dimensional wide-band semiconducting lead iodide (PbI2). The photocurrent under visible light showed abrupt increases by two orders of magnitude at ≈25 GPa, where the crystalline structure transforms from the Pnma to I4/MMM phase. The responding band expanded from visible light to at least the telecom wavelength 1550 nm. The spectra of PbI2 suggested that […]